Simplify internal metadata class. (#16762)

We remove these fields as they're just duplicating data the event
already stores, and (for reasons :shushing_face:) I'd like to simplify
the class to only store simple types.

I'm not entirely convinced that we shouldn't instead add helper methods
to the event class to generate stream tokens, but I don't really think
that's where they belong either

1 files changed, 8 insertions, 2 deletions

diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py

index e78e598d5e..41b00a5cf7 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -1742,13 +1742,19 @@ class RoomEventSource(EventSource[RoomStreamToken, EventBase]):
             events = list(room_events)
             events.extend(e for evs, _ in room_to_events.values() for e in evs)
 
-            events.sort(key=lambda e: e.internal_metadata.order)
+            # We know stream_ordering must be not None here, as its been
+            # persisted, but mypy doesn't know that
+            events.sort(key=lambda e: cast(int, e.internal_metadata.stream_ordering))
 
             if limit:
                 events[:] = events[:limit]
 
             if events:
-                end_key = events[-1].internal_metadata.after
+                last_event = events[-1]
+                assert last_event.internal_metadata.stream_ordering
+                end_key = RoomStreamToken(
+                    stream=last_event.internal_metadata.stream_ordering,
+                )
             else:
                 end_key = to_key